Blood Alcohol Testing

Blood alcohol testing undertaken by a Clinical Pathology Accredited laboratory

  • Carbohydrate Deficient Transferrin (CDT) and Liver Function (LF) testing help in the assessment of short term excessive alcohol use
  • Sample collections by professionally trained phlebotomists
  • Analysis Results accepted by all UK courts issued in 5 working days or less
  • Two different types of blood tests for an accurate interpretation
  • Provides a comprehensive picture of historic chronic excessive alcohol use when used in conjunction with hair alcohol testing

Blood Testing for Alcohol Markers

Lextox offers both Liver Function (LF) and Carbohydrate Deficient Transferrin (CDT) blood testing. We recommend a combined analysis of these alcohol biomarkers to help provide you with a better picture of alcohol use.

Liver Function Testing (LFT)

A liver function test is used to help assess liver damage and consists of a number of tests that are run at the same time. Any damage to the liver alters the biomarkers in the blood stream allowing any impairment to be highlighted.

A liver function test will provide a snap shot in time of potential liver damage through excessive alcohol use. Regular heavy drinking can affect a number of enzymes and proteins involved in liver function; the most widely used to indicate heavy alcohol consumption are aspartate transferase (AST), alanine transferase (ALT) and gamma GT (GGT). However elevation of these biomarkers may also be due to  medications or health problems.

Carbohydrate Deficient Transferrin (CDT)

A carbohydrate deficient transferrin test measures the percentage of transferrin (a protein that transports iron around the body) in the blood that is deficient in carbohydrate. Alcohol consumption can interfere with the binding of carbohydrate molecules to transferrin, causing elevated levels of transferrin that are missing the carbohydrate molecule.

Excessive alcohol consumption over the 2-4 week period prior to the test or longer, can elevate the total percentage of transferrin that is carbohydrate deficient and thus is a good marker to help assess recent alcohol use.

Blood tests are unable to provide a definitive assessment of alcohol use and we recommend that they are not used in isolation. Blood alcohol analysis should form part of the evidential picture when trying to assess an individual’s chronic alcohol use and it is recommended they are used in conjunction with other evidence, such as hair alcohol marker testing.

For more information or advice on our blood alcohol testing services, please call us on 029 2048 4141 or email

What time period can CDT and liver function blood testing cover?
The blood tests for alcohol markers can help to show recent excessive alcohol use. A liver function test is a snap shot in time of the liver function and damage, whereas a CDT test can highlight excessive alcohol consumption over the past 2-4 weeks or longer
Why are both LF and CDT testing used?
It is recommended that both liver function and carbohydrate deficient transferrin tests are used together to obtain a better picture of alcohol use. Each test looks for different markers so when combined together they can provide mutual confirmation and a greater degree of certainty. A single test in isolation may lead to a misinterpretation of alcohol use.